JPH0663847U - Cylinder head bolt for midstop liner - Google Patents

Abstract

(57) [Abstract] [Purpose] In a reciprocating internal combustion engine equipped with a mid-stop liner, the tensile stress generated in the cylinder block is reduced by tightening the cylinder head bolts.
Achieves a lightweight cylinder block. [Structure] The length L1 of the portion of the cylinder head bolt 3 that is screwed into the cylinder block 1 is set to be equal to or greater than the depth L2 from the upper surface of the cylinder block 1 to the step surface 1a with which the midstop liner 2 abuts. As a result, the structure above the step surface 2a of the mid-stop liner 2 is sandwiched between the cylinder head and the portion below the step surface 1a. The tensile stress generated in the cylinder block 1 by the tightening of the cylinder head bolt 3 moves below the step surface 1a, and the tensile stress applied to the peripheral portion of the water jacket 1b is reduced. Therefore, the wall thickness of the water jacket 1b can be made thinner than before, and the weight of the cylinder block 1 can be reduced.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a cylinder head bolt for a midstop liner.

[0002]

[Prior art]

 In a reciprocating drive type internal combustion engine in which a wet cylinder liner is fitted to the piston sliding portion of the cylinder block, a step surface 2a is provided on the outer periphery of the central portion of the cylinder liner 2 as shown in FIG. A mid-stop liner is used that fixes the axial position of the cylinder liner 2 with respect to the cylinder block 1 by bringing it into contact with a step surface 1a provided in the cylinder bore of the block 1. Since the slap position of the midstop liner 2 is located at the axial center of the liner 2, noise is reduced. Further, there is an advantage that the deformation of the lower end of the liner is small.

[0003]

[Problems to be solved by the device]

 In FIG. 2, a cylinder head and a head gasket (not shown) are attached to the cylinder block 1 by using a cylinder head bolt 3. Since the screw-in depth L1 of the cylinder head bolt 3 with respect to the cylinder block 1 is shorter than the depth L2 from the upper surface of the cylinder block 1 to the step surface 1a with which the mid stop liner 2 abuts, the screwing of the head bolt 3 in the cylinder block 1 is performed. A tensile stress due to the tightening of the head bolt 3 acts on the portion sandwiched between the lower end of the portion and the step surface 1a. Therefore, in order to increase the rigidity of the cylinder block 1, it is necessary to increase the wall thickness around the water jacket 1b, which causes a problem that the weight of the cylinder block increases. The present invention has been made in view of the above-mentioned conventional problems, and it reduces the tensile stress generated in the cylinder block by tightening the cylinder head bolts and enables the cylinder block to be made lighter in weight. The purpose is to provide a head bolt.

[0004]

In order to achieve the above object, a cylinder head bolt for a mid-stop liner according to the present invention is provided with a step surface provided on an outer periphery of a central portion of a cylinder liner in an axial direction in a cylinder bore of a cylinder block. In a reciprocating drive type internal combustion engine equipped with a mid-stop liner for fixing the axial position of the cylinder liner with respect to the cylinder block by contacting it with a step surface, a cylinder head for attaching the cylinder head to the cylinder block. The length L1 of screwing the bolt into the cylinder block is not less than the depth L2 from the upper surface of the cylinder block to the step surface with which the midstop liner abuts.

[0005]

[Action]

 According to the above configuration, the length L1 of the portion of the cylinder head bolt that attaches the cylinder head to the cylinder block is screwed into the cylinder block, and the depth L2 from the upper surface of the cylinder block to the step surface with which the midstop liner abuts. Because of the above, the part above the step surface of the mid-stop liner will be sandwiched by the part below the step surface of the cylinder block and the cylinder head when the cylinder head bolt is tightened. Therefore, the tensile stress generated in the cylinder block moves below the step surface of the cylinder block. Therefore, the tensile stress applied to the peripheral portion of the water jacket is reduced, and the thickness of this portion can be made thinner than before.

[0006]

【Example】

 An embodiment of a cylinder head bolt for a midstop liner according to the present invention will be described below with reference to the drawings. FIG. 1 is a partial cross-sectional view of a cylinder head bolt fastened to a cylinder block and its surroundings. 1 is a cylinder block, 2 is a mid-stop liner, 3 is a cylinder head bolt, and 4 and 5 are O-rings. A step surface 2a is provided on the outer periphery of the central portion of the mid-stop liner 2 in the axial direction. By contacting the step surface 2a with the step surface 1a provided on the cylinder bore of the cylinder block 1, the mid-stop liner 2 The axial position of is fixed. Then, when the head bolt 3 is tightened to attach the cylinder head and the head gasket (not shown) to the cylinder block 1, the step surface 2a comes into close contact with the step surface 1a. The head bolt 3 is set such that the length L1 of the portion screwed into the cylinder block 1 is not less than the depth L2 from the upper surface of the cylinder block 1 to the step surface 1a with which the mid stop liner 2 abuts. ing.

If the length of the cylinder head bolt 3 is set as described above, when the cylinder head bolt 3 is tightened, the portion above the step surface 2a of the mid-stop liner 2 is the step surface of the cylinder head and the cylinder block 1. The structure is sandwiched between the portion below 1a. The tensile stress generated in the cylinder block 1 by the tightening of the cylinder head bolt 3 moves below the step surface 1a, and the tensile stress applied to the peripheral portion of the water jacket 1b is reduced. Therefore, the wall thickness of the water jacket 1b can be made thinner than before, and the weight of the cylinder block 1 can be reduced.

[0008]

[Effect of device]

 As described above, according to the present invention, in the cylinder head bolt for attaching the cylinder head to the cylinder block, the length L1 of the portion screwed into the cylinder block is determined by the step surface with which the midstop liner abuts from the upper surface of the cylinder block. Up to a depth of L2 or more, and the part above the step surface of the mid-stop liner is sandwiched by the part below the step surface of the cylinder block and the cylinder head. The generated tensile stress moves below the step surface of the cylinder block. Therefore, the tensile stress applied to the peripheral portion of the water jacket is reduced, and the wall thickness of this portion can be made thinner than before, so that the weight of the cylinder block can be reduced.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a cylinder head bolt fastened to a cylinder block and its periphery.

FIG. 2 is a partial cross-sectional view of a cylinder block to which a cylinder head bolt is fastened according to a conventional technique.

[Explanation of symbols]

 1 Cylinder block 1a, 2a Step surface 2 Mid stop liner (cylinder liner) 3 Cylinder head bolt

Claims (1)

[Scope of utility model registration request] 1. A midstop liner for fixing an axial position of a cylinder liner with respect to the cylinder block by bringing a step surface provided on an outer periphery of an axial center portion of the cylinder liner into contact with a step surface provided on a cylinder bore of the cylinder block. In a reciprocating drive type internal combustion engine equipped with, the screwing length L1 of the cylinder head bolt for attaching the cylinder head to the cylinder block to the cylinder block is
A cylinder head bolt for a midstop liner, wherein a depth L2 from a top surface of the cylinder block to a step surface with which the midstop liner abuts is not less than L2.